Mountain pine beetle populations increased in 1979 in the Thompson River drainage to levels predicted following the 1978 attack period. New attacks in 1979 averaged 27 per acre. Current estimates indicate another 25 percent of the remaining lodgepole pine could be killed in 1980.
Methods used to establish permanent plots in precommercially thinned and unthinned stands to monitor root disease development are described. Plots were established in 22 Armillaria-infested stands in northern Idaho and western Montana. The proportion of trees dead and infected was significantly higher for planted than for natural regeneration at the...
A synthetic pheromone of the western pine shoot borer, Eucosma sonomana Kearfott, has been used
successfully as a 'mating disrupter in northern Idaho and western Montana since 1984. Infestation
levels in treated ponderosa pine plantations declined from an average of 28 percent infested in 1983
to 5.5 percent by 1986....
Six Montana areas in which permanent mountain pine beetle trend plots were established in 1979 were revisited in 1980. Results of the visit show infestation intensity decreased significantly in Centennial Valley, decreased slightly in the Madison River plot area, and increased almost threefold in the Murr Creek area. Beetle populations...
An active infestation of ash borer, Podosesia syringae (Harris) was detected in green ash, Fraxinus pennsylvanica Marsh, surrounding the Bowman-Haley Reservoir in 1973. A survey in 1974 showed that 40.4 percent of 690 trees examined contained active ash borer attacks. Forty-three out of 140 windbreaks were sampled and each one...
The Douglas-fir tussock moth, Orgyia pseudotsugata McD., periodically
defoliates Douglas-fir, true firs, and other host trees in forests of
the western United States. In the Northern Region, these infestations
occur about once every decade.
This history covers the earliest recorded outbreak in northeastern
Washington from 1928 to 1930 and includes...
"Holes" with dead, dying, and downed trees in the forest canopy could be reliably identified on 9- by 9-inch Kodak Ektachrome Infrared Aero film 2443 as root disease centers. Film scales larger than 1:4000 were best for detection of these "holes."
Most commonly occurring causal organisms in root diseased trees...